The present disclosure relates to complex three dimensional (3D) polymer nanoscale materials and methods of forming the same. More specifically, the present disclosure relates to the use of hexahydrotriazine (HT) and hemiaminal (HA) molecules, oligomers, and polymers derived from aromatic, aliphatic, and/or polyether amines to create dynamic covalent 3D nano-objects.
Polymer architecture or chain topology, and the ability to manipulate the macromolecular topology, is generally considered to be important in modern polymer chemistry. Complex polymer architectures may exist as 3D, discrete, nanoscale objects. The 3D nanoscale objects generally exhibit different physical properties when compared to similar linear counterparts of similar composition. Manufacture of 3D polymer architectures has typically been through either of two approaches: covalent or supramolecular.
One example of supramolecular 3D nano-objects are diblock copolymers. If the physical properties of different block comprising the diblock copolymer differ to a requisite degree, the block may microphase separate to form complex morphologies. If the physical properties of the two different blocks in the diblock copolymer are very different, for example, amphiphilic block copolymers, discrete supramolecular block copolymer assemblies may be formed as a result of hydrophobic/hydrophilic interactions. The formation of amphiphilic block copolymer assemblies is driven by the reduction of surface tension between the hydrophobic portion of the amphiphilic molecule in an aqueous environment. As such, the amphiphilic block copolymer assemblies exhibit both hydrophobic and hydrophilic properties.
The most common example of an amphiphilic block copolymer assembly is the micelle. Micelles exist as equilibrium structures defined generally by two parameters: the critical micelle concentration (CMC) and aggregation number (Naagg). The CMC is the concentration above which the amphiphilic components must be present in the assembly to self-assemble in a polar solvent, such as water. The Nagg is the number of molecules that are necessary to form a complete micelle, which controls the size of the nanostructure formed. Micelles as supramolecular nanoscale objects are useful for many applications, including biomedical applications, but may be limited in application due to the reversible nature of micelle formation and the instability of micellular systems at concentrations below the CMC in certain environments.
One example of covalent 3D unimolecular polymer nano-objects are dendrimers. Covalent polymer architectures are an attractive alternative to self-assembled micelles because the covalent architectures are generally more structurally robust and exist as non-equilibrium structures. However, current covalent polymer architectures (i.e. dendrimers) are often derived from complex and economically inefficient traditional organic synthesis. Covalent polymer architectures are useful for various applications due to the molecular size and controllable structure of the polymers, but are often limited in application due to the relative inefficiency associated with formation of the polymer.
Thus, what is needed in the art are improved methods and materials for forming covalent 3D nano-objects.